Galenical formulations

ABSTRACT

A pharmaceutical composition containing macrolide, e.g. a rapamycin compound in an emulsion preconcentrate or microemulsion preconcentrate for oral administration. The carrier medium for the rapamycin compound includes a hydrophilic phase, a lipophilic phase and a surfactant. The composition is stable and provides high absorption efficiency.

[0001] This invention relates to galenic formulations containingmacrolides, e.g. compounds of the rapamycin class. In particular thisinvention relates to galenic formulations which are in the form ofmicro-emulsions, micro-emulsion preconcentrates, emulsion oremulsion-preconcentrate.

[0002] The macrolide may contain e.g. 1, 2 or 3 ring oxygen or nitrogenor other atoms besides carbon atoms. It may have side chains, e.g. inthe form of fused rings, or substituents, e.g. oxy groups. It maycontain double bonds. It may contain e.g. from 15 to 35 ring atoms e.g.of carbon.

[0003] Rapamycin is a macrolide antibiotic produced by Streptomyceshygroscopicus. It has been found to be pharmaceutically useful in avariety of applications, particularly as an immunosuppressant for use inthe treatment and prevention of organ transplant rejection andautoimmune diseases. Rapamycin has the following structure:

[0004] (Kesseler, H., et al., Helv. Chim. Acta (1993) 76: 117; U.S. Pat.No. 3,929,992). Large numbers of derivatives of rapamycin have beensynthesized, including for example those disclosed in U.S. Pat. Nos.5,221,670 and 5,221,740, certain acyl and aminoacyl-rapamycins (see forexample U.S. Pat. No. 4,316,885, U.S. Pat. No. 4,650,803, and U.S. Pat.No. 5,151,413), and carbonates and amide esters (see for example EP509795 and 515140) 27-desmethyl-rapamycin (see for example WO 92/14737),26-dihydro-rapamycin (see for example U.S. Pat. No. 5,138,051),alkoxyester derivatives (see for example U.S. Pat. No. 5,233,036), andcertain pyrazole derivatives (U.S. Pat. No. 5,164,399).

[0005] Rapamycin and its structurally similar analogs and derivativesare termed collectively as “compounds of the rapamycin class” in thisspecification.

[0006] Compounds of the rapamycin class are extremely potentimmunosuppressants and have also been shown to have antitumor andantifungal activity. However their utility as pharmaceuticals.especiallyon oral administration has been restricted by their very low solubility,low and variable bioavailability and their high toxicity. Little isknown concerning the causes of these properties and the site ofabsorption. Thus low bioavailability may be thought to due to due toextensive metabolism of the macrolide ring and not solvable by agalenical formluation. Therefore there is a need for an acceptablepharmaceutical composition that contains compounds of the rapamycinclass.

[0007] FK506 is a macrolide immunosuppressant that is produced byStreptomyces tsukubaensis No 9993. The structure of FK506 is given inthe appendix to the Merck Index, as item A5. Also a large number ofrelated compounds which retrain the basic structure and immunologicalproperties of FK506 are also known. These compounds are described in alarge number of publications, for example EP 184162, EP 315973, EP323042, EP 423714, EP 427680, EP 465426, EP 474126, WO 91/13889, WO91/19495, EP 484936, EP 532088, EP 532089, WO 93/5059 and the like.Little is known concerning the biopharmaceutical properties of suchcompounds. These compounds are termed collectively “FK506 compounds” inthis specification.

[0008] It has now been surprisingly found that stable compositionscontaining macrolides that offer high absorption efficiency, can beobtained by formulating the macrolide with certain carrier media.

[0009] Accordingly, this invention provides a pharmaceutical compositioncomprising a macrolide and a carrier medium comprising a hydrophilicphase, a lipophilic phase and a surfactant.

[0010] In another aspect the invention provides a pharmaceuticalcomposition which comprises an orally administrable active agent whichis other than a cyclosporin and a microemulsion preconcentrate carriermedium therefor which comprises

[0011] i) a reaction product of castor oil and ethylene oxide,

[0012] ii) a transesterification product of a vegetable oil and glycerolcomprising predominantly linoleic acid or oleic acid mono-, di- andtri-glycerides, or a polyoxyalkylated vegetable oil,

[0013] iii) 1,2 propylene glycol and

[0014] iv) ethanol.

[0015] The pharmaceutical composition is stable and results insurprisingly high and consistent absorption efficiency when administeredorally. Therefore the macrolide may be administered in lower doses,which alleviates toxicity problems. For example, in animal trials inwhich the pharmaceutical compositions are administered orally, thepharmaceutical compositions resulted in high bioavailabilities. Hencethe pharmaceutical compositions have very surprising properties whichoffer great advantages.

[0016] Preferably the composition is in the form of a “microemulsionpreconcentrate” or “emulsion preconcentrate”, in particular of the typeproviding o/w (oil-in-water) microemulsions or emulsions. However thecomposition may be in the form of a microemulsion or an emulsion whichadditionally contains an aqueous phase; preferably water.

[0017] A “microemulsion preconcentrate” is defined in this specificationas being a formulation which spontaneously forms a microemulsion in anaqueous medium, for example, in water or in the gastric juices afteroral application.

[0018] A “microemulsion” is a non-opaque or substantially non-opaquecolloidal dispersion that is formed spontaneously or substantiallyspontaneously when its components are brought into contact. Amicroemulsion is thermodynamically stable and contains dispersedparticles of a size less than about 2000 Å. Generally microemulsionscomprise droplets or particles having a diameter of less than about 1500Å; typically from 30 to 1000 Å. Further characteristic can be found inBritish patent application 2 222 770 A; the disclosure of which isincorporated herein by reference.

[0019] An “emulsion preconcentrate” is defined in this specification asbeing as being a formulation which spontaneously forms an emulsion in anaqueous medium, for example, in water or in the gastric juices afteroral application. The emulsion formed is opaque, thermodynamicallystable and contains dispersed droplets of a size greater than about 100nm, more usually greater than about 200 nm. Often bimodal size rangedistributions are obtained. The emulsion preconcentrates are preferablyof the type providing o/w (oil-in-water) emulsions.

[0020] A “pharmaceutical composition” means a composition in which theindividual components or ingredients are themselves pharmaceuticallyacceptable and, when a particular form of administration is foreseen,are suitable or acceptable for that form of administration.

[0021] The lipophilic phase may comprise 10 to 85% by weight of thecarrier medium; preferably 15 to 70% by weight, more preferably 20 to60% by weight and even more preferably about 25% by weight.

[0022] The surfactant may comprise 5 to 80% by weight of the carriermedium; preferably 10 to 70% by weight, more preferably 20 to 60% byweight and even more preferably about 40% by weight.

[0023] The hydrophilic phase may comprise 10 to 50% by weight of thecarrier medium; preferably 15 to 40% by weight, more preferably 20 to35% by weight and even more preferably about 30% by weight.

[0024] The macrolide is preferably present in an amount of 1 to 15% byweight of the composition; more preferably about 2 to 10%.

[0025] The macrolide may be rapamycin or an O-substituted derivative inwhich the hydroxy in position 40 of the formula illustrated above isreplaced by —OR₁ in which R₁ is hydroxyalkyl, hydroalkoxyalkyl,acylaminoalkyl and aminoalkyl; for example40-O-(2-hydroxy)ethyl-rapamycin, 40-O-(3-hydroxy)propyl-rapamycin,40-O-[2-(2-hydroxy)ethoxy]ethyl-rapamycin and40-O-(2-acetaminoethyl)-rapamycin. These O-substituted derivatives maybe produced by reacting Rapamycin (or dihydro or deoxorapamycin) with anorganic radical attached to a leaving group (for example RX where R isthe organic radical which is desired as the O-substituent, such as analkyl, allyl, or benzyl moiety, and X is a leaving group such asCCl₃C(NH)O or CF₃SO₃) under suitable reaction conditions. The conditionsmay be acidic or neutral conditions, for example in the presence of anacid like trifluoromethanesulfonic acid, camphorsulfonic acid,p-toluenesulfonic acid or their respective pyridinium or substitutedpyridinium salts when X is CCl₃C(NH)O or in the presence of a base likepyridine, a substituted pyridine, diisopropylethylamine orpentamethylpiperidine when X is CF₃SO₃.

[0026] A preferred compound is 40-0-(2-hydroxy)ethyl rapamycin(hereinafter compound A) as disclosed in PCT/EP/93/02604

[0027] Examples of compounds of the FK 506 class are those mentionedabove. They include for example FK 506, ascomycin and other naturallyoccuring compounds. They include also synthetic analogues.

[0028] A preferred compound of the FK 506 class is disclosed in EP 427680, e.g. Example 66a. Other preferred compounds are disclosed in EP 465426.

[0029] The hydrophilic phase may be selected from Transcutol (which hasthe formula C₂H₅—[O—(CH₂)₂]₂—OH), Glycofurol (also known astetrahydroturfuryl alcohol polyethylene glycol ether) and 1,2-propyleneglycol, or mixtures thereof, and is preferably 1,2-propylene glycol. Thehydrophilic phase may include further hydrophilic co-components, forexample lower alkanols such as ethanol. These co-components willgenerally be present in partial replacement of other components of thehydrophilic phase. While the use of ethanol in the compositions is notessential, it has been found to be of particular advantage when thecompositions are to be manufactured in soft gelatine, encapsulated form.This is because storage characteristics are improved, in particular therisk of rapamycin precipitation following encapsulation procedures isreduced. Thus the shelf life stability may be extended by employingethanol or some other such co-component as an additional ingredient ofthe hydrophilic phase. The ethanol may comprise 0 to 60% by weight ofthe hydrophilic phase; preferably 20 to 55% by weight and morepreferably about 40 to 50% by weight. Small quantities of liquidpolyethylene glycols may also be included in the hydrophilic phase.

[0030] Preferred lipophilic phase components are medium chain fatty acidtriglycerides, mixed mono-, di-, tri-glycerides, and transesterifiedethoxylated vegetable oils.

[0031] Suitable medium chain fatty acid triglycerides are those knownand commercially available under the trade names Miglyol, Captex,Myritol, Capmul, Captex, Neobee and Mazol; Miglyol 812 being the mostpreferred. These triglycerides are described in Fiedler, H. P. “Lexikonder Hilfsstoffe für Pharmazie, Kosmetik und angrenzende Gebiete”, EditioCantor, D-7960 Aulendorf, 3rd revised and expanded edition (1989), thecontents of which are hereby incorporated by reference.

[0032] The mixed mono-, di-, tri-glycerides preferably comprise mixturesof C₁₂₋₂₀ fatty acid mono-, di- and tri-glycerides, especially mixedC₁₆₋₁₈ fatty acid mono-, di- and triglycerides. The fatty acid componentof the mixed mono-, di- and tri-glycerides may comprise both saturatedand unsaturated fatty acid residues. Preferably however they arepredominantly comprised of unsaturated fatty acid residues; inparticular C₁₈ unsaturated fatty acid residues. Suitably the mixedmono-, di-, tri-glycerides comprise at least 60%, preferably at least75%, more preferably at least 85% by weight of a C₁₈ unsaturated fattyacid (for example linolenic, linoleic and oleic acid) mono-, di- andtri-glycerides. Suitably the mixed mono-, di-, tri-glycerides compriseless than 20%, for example about 15% or 10% by weight or less, saturatedfatty acid (for example palmitic and stearic acid) mono-, di- andtri-glycerides.

[0033] The mixed mono-, di-, tri-glycerides are preferably predominantlycomprised of mono- and di-glycerides; for example mono- anddi-glycerides comprise at least 50%, more preferably at least 70% basedon the total weight of the lipophilic phase. More preferably, the mono-and di-glycerides comprise at least 75% (for example about 80% or 85% byweight of the lipophilic phase.

[0034] Preferably the monoglycerides comprise from about 25 to about50%, based on the total weight of the lipophilic phase, of the mixedmono-, di-, tri-glycerides. More preferably from about 30 to about 40%(for example 35 to 40%) monoglycerides are present.

[0035] Preferably the diglycerides comprise from about 30 to about 60%,based on the total weight of the lipophilic phase, of the mixed mono-,di-, tri-glycerides. More preferably from about 40 to about 55% (forexample 48 to 50%) diglycerides are present.

[0036] The triglycerides suitably comprise at least 5% but less thanabout 25%, based on the total weight of the lipophilic phase, of themixed mono-, di-, tri-glycerides. More preferably from about 7.5 toabout 15% (for example from about 9 to 12%) triglycerides are present.

[0037] The mixed mono-, di-, tri-glycerides may be prepared by admixtureof individual mono-, di- or tri-glycerides in appropriate relativeproportion. Conveniently however they comprise transesterificationproducts of vegetable oils, for example almond oil, ground nut oil,olive oil, peach oil, palm oil or, preferably, corn oil, sunflower oilor safflower oil and most preferably corn oil, with glycerol.

[0038] Such transesterification products are generally obtained byheating the selected vegetable oil with glycerol, at high temperature inthe presence of an appropriate catalyst under an inert atmosphere withcontinuous agitation (for example in a stainless steel reactor) toeffect trans-esterification or glycerolysis. In addition to their mono-,di- and tri-glyceride components, the transesterification products alsogenerally comprise minor amounts of free glycerol. The amount of freeglycerol present is preferably less than 10%, more preferably less than5%, most preferably about 1 or 2% by weight based on the total weight offree glycerol plus mono-, di- and tri-glycerides.

[0039] Preferably some of the glycerol is first removed to give a“substantially glycerol free batch” when soft gelatine capsules are tobe made.

[0040] Trans-esterification products of corn oil and glycerol provideparticularly suitable mixed mono-, di-, and tri-glycerides. An exampleof a suitable mixed glyceride product is the trans-esterificationproduct commercially available under the trade name MAISINE. Thisproduct is comprised predominantly of linoleic and oleic acid mono-, di-and tri-glycerides together with minor amounts of palmitic and stearicacid mono-, di- and tri-glycerides (corn oil itself being comprised ofabout 56% by weight linoleic acid, 30% oleic acid, about 10% palmiticand about 3% stearic acid constituents). The physical characteristics ofMAISINE [available from the company Etablissements Gattefossé, of 36,Chemin de Genas, P.O. Box 603, 69804 Saint-Priest, Cedex (France)] are:up to 10% (typically 3.9 to 4.9% or, in “substantially glycerol free”batches, about 0.2%) free glycerol; about 35% (typically 30 to 40% or,in “substantially glycerol free” batches, about 32 to 36%, for exampleabout 36%) mono-glycerides; about 50% (or, in “substantially glycerolfree” batches about 46 to 48%) di-glycerides; about 10% (or, in“substantially glycerol free” batches, about 12 to 15%) tri-glycerides;and about 1% free oleic acid.

[0041] Further physical characteristics for MAISINE are: an acid valueof maximum about 2, an iodine no. of about 85 to 105, a saponificationno. of about 150 to 175 (Fiedler “Lexikon der Hilfsstoffe”, 3rd revisedand expanded edition (1989) Vol. 2, p.768). The fatty acid content forMAISINE is typically: about 11% palmitic acid; about 2.5% stearic acid;about 29% oleic acid; about 56% linoleic acid; and 1.5% other acids.

[0042] It is especially preferred that the mixed mono-, di-, andtri-glycerides are clear and remain clear for more than 20 days uponstorage at temperatures of 20° C. to 25° C. Also, a sample of the mixedmono-, di-, and tri-glycerides, which has been kept in a refrigerator atabout between 2 and 8° C. for 24 hours and then held at room temperaturefor 1 hour, should be clear.

[0043] Preferably the mono-, di-, tri-glycerides have a low saturatedfatty acid content. Mixed mono-, di-, tri-glycerides meeting theserequirements may be obtained from commercially available products byseparation techniques as known in the art (for example freezingprocedures coupled with separation techniques such as centrifugation) toremove the saturated fatty acid components and enhance the unsaturatedfatty acid component content. Typically the total saturated fatty acidcomponent content will be less than 15%, (for example <10%, or <5%) byweight based on the total weight of the lipophilic phase. A reduction ofthe content of saturated fatty acid component in the mono-glyceridefraction may be observed after being subjected to the separationtechnique. A suitable process is described in WO 93/09211.

[0044] The mixed mono-, di-, tri-glycerides thus preferably containlesser quantities of saturated fatty acids (e.g. palmitic and stearicacids) and relatively greater quantities of unsaturated fatty acids(e.g. oleic and linoleic acids) than the starting material.

[0045] A suitable example of a mixed mono-, di-, tri-glyceride productcontaining lesser quantities of saturated fatty acids contains : 32 to36% mono-glycerides, 45 to 55% di-glycerides and 12 to 20%tri-glycerides, by weight based on the total weight of the lipophilicphase. Further characteristics include the following: Fatty acid contentMethyl linoleate 53 to 63%, (as determined as Methyl oleate 24 to 34%,the methyl ester by Methyl linolenate 0 to 3% chromatography) Methylarachate 0 to 3%, Methyl palmitate 6 to 12%, Methyl stearate 1 to 3%Relative Density 0.94 to 0.96 Hydroxyl Value  140 to 210 Iodine Value 110 to 20 Peroxide Value <4.0 Free Glycerol <1.0 Saponification noabout 150 to 185 Acid value max. about 2

[0046] Mixed mono-, di-, tri-glycerides complying with thesecharacteristics are referred to in this specification as “refinedglycerol-transesterified corn oils”. The “refinedglycerol-transesterified corn oils” have the advantage of remainingstable for a long time.

[0047] The lipophilic phase may alternatively comprise suitabletransesterified ethoxylated vegetable oils such as those obtained byreacting various natural vegetable oils (for example, maize oil, kerneloil, almond oil, ground nut oil, olive oil, soybean oil, sunflower oil,safflower oil and palm oil, or mixtures thereof) with polyethyleneglycols that have an average molecular weight of from 200 to 800, in thepresence of an appropriate catalyst. These procedures are known and anexample is described in U.S. Pat. No. 3,288,824. Transesterifiedethoxylated corn oil is particularly preferred.

[0048] Transesterified ethoxylated vegetable oils are known and arecommercially available under the trade name LABRAFIL (H. Fiedler, loccit, vol 2, page 707). Examples are LABRAFIL M 2125 CS (obtained fromcorn oil and having an acid number of less than about 2, asaponification number of 155 to 175, an HLB value of 3 to 4, and aniodine number of 90 to 110), and LABRAFIL M 1944 CS (obtained fromkernel oil and having an acid number of about 2, a saponification numberof 145 to 175 and an iodine number of 60 to 90). LABRAFIL M 2130 CS(which is a transesterification product of a C₁₂₋₁₈ glyceride andpolyethylene glycol and which has a melting point of about 35 to 40° C.,an acid number of less than about 2, a saponification number of 185 to200 and an iodine number of less than about 3) may also be used. Thepreferred transesterified ethoxylated vegetable oil is LABRAFIL M 2125CS which can be obtained, for example, from Gattefossé, Saint-PriestCedex, France.

[0049] Examples of suitable surfactants are:

[0050] i) reaction products of a natural or hydrogenated castor oil andethylene oxide. The natural or hydrogenated castor oil may be reactedwith ethylene oxide in a molar ratio of from about 1:35 to about 1:60,with optional removal of the polyethyleneglycol component from theproducts. Various such surfactants are commercially available. Thepolyethyleneglycol-hydrogenated castor oils available under the tradename CREMOPHOR are especially suitable. Particularly suitable areCREMOPHOR RH 40, which has a saponification number of about 50 to 60, anacid number less than about 1, a water content (Fischer) less than about2%, an n_(D) ⁶⁰ of about 1.453 to 1.457 and an HLB of about 14 to 16;and CREMOPHOR RH 60, which has a saponification number of about 40 to50, an acid number less than about 1, an iodine number of less thanabout 1, a water content (Fischer) of about 4.5 to 5.5%, an n_(D) ²⁵ ofabout 1.453 to 1.457 and an HLB of about 15 to 17. An especiallypreferred product of this class is CREMOPHOR RH40. Also suitable arepolyethyleneglycol castor oils such as that available under the tradename CREMOPHOR EL, which has a molecular weight (by steam osmometry) ofabout 1630, a saponification number of about 65 to 70, an acid number ofabout 2, an iodine number of about 28 to 32 and an n_(D) ²⁵ of about1.471. Similar or identical products which may also be used areavailable under the trade names NIKKOL (e.g. NIKKOL HCO-40 and HCO-60),MAPEG (e.g. MAPEG CO-40h), INCROCAS (e.g. INCROCAS 40), and TAGAT (e.g.TAGAT RH 40). These surfactants are further described in Fiedler loc.cit.

[0051] ii) Polyoxyethylene-sorbitan-fatty acid esters, for example mono-and tri-lauryl, palmityl, stearyl and oleyl esters of the type known andcommercially available under the trade name TWEEN (Fiedler, loc.cit.p.1300-1304) including the products TWEEN

[0052] 20 [polyoxyethylene(20)sorbitanmonolaurate],

[0053] 21 [polyoxyethylene(4)sorbitanmonolaurate],

[0054] 40 [polyoxyethylene(20)sorbitanmonopalmitate],

[0055] 60 [polyoxyethylene(20)sorbitanmonostearate],

[0056] 65 [polyoxyethylene(20)sorbitantristearate],

[0057] 80 [polyoxyethylene(20)sorbitanmonooleate],

[0058] 81 [polyoxyethylene(5)sorbitanmonooleate],

[0059] 85 [polyoxyethylene(20)sorbitantrioleate].

[0060] Especially preferred products of this class are TWEEN 40 andTWEEN 80.

[0061] iii) Polyoxyethylene fatty acid esters, for examplepolyoxyethylene stearic acid esters of the type known and commerciallyavailable under the trade name MYRJ (Fiedler, loc. cit., 2, p.834-835).An especially preferred product of this class is MYRJ 52 having a D²⁵ ofabout 1.1., a melting point of about 40 to 44° C., an HLB value of about16.9., an acid value of about 0 to 1 and a saponification no. of about25 to 35.

[0062] iv) Polyoxyethylene-polyoxypropylene co-polymers and blockco-polymers, for example of the type known and commercially availableunder the trade names PLURONIC, EMKALYX and POLOXAMER (Fiedler, loc.cit., 2, p. 959). An especially preferred product of this class isPLURONIC F68, having a melting point of about 52° C. and a molecularweight of about 6800 to 8975. A further preferred product of this classis POLOXAMER 188.

[0063] v) Dioctylsulfosuccinate or di-[2-ethylhexyl]-succinate (Fiedler,loc. cit., 1, p. 107-108).

[0064] vi) Phospholipids, in particular lecithins (Fiedler, loc. cit.,2, p. 943-944). Suitable lecithins include, in particular, soya beanlecithins.

[0065] vii) Propylene glycol mono- and di-fatty acid esters such aspropylene glycol dicaprylate (also known and commercially availableunder the trade name MIGLYOL 840), propylene glycol dilaurate, propyleneglycol hydroxystearate, propylene glycol isostearate, propylene glycollaurate, propylene glycol ricinoleate, propylene glycol stearate and soforth (Fiedler, loc. cit., 2, p. 808-809).

[0066] It will also be appreciated that the components of the carriermedium may contain unreacted starting materials, e.g. polyethyleneglycol.

[0067] The surfactant selected preferably has an HLB of at least 10.

[0068] Preferably the relative proportion of hydrophilic phasecomponent(s), the lipophilic phase and the surfactant lie within the“microemulsion” region on a standard three way plot. The compositionsthus obtained are microemulsion preconcentrates of high stability thatare capable, on addition to water, of providing microemulsions having anaverage particle size of <1.500 Å and stable over periods in excess of24 hours.

[0069] The microemulsion preconcentrate compositions show good stabilitycharacteristics as indicated by standard stability trials, for examplehaving a shelf life stability of up to three years, and even longer.

[0070] Alternatively the components may be selected to provide anemulsion preconcentrate. The emulsion preconcentrate compositions alsoshow good stability characteristics as indicated by standard stabilitytrials, for example having a shelf life stability of up to three years,and even longer.

[0071] The pharmaceutical composition may also include further additivesor ingredients, for example antioxidants (such as ascorbyl palmitate,butyl hydroxy anisole (BHA), butyl hydroxy toluene (BHT) andtocopherols) and/or preserving agents. These additives or ingredientsmay comprise about 0.05 to 1% by weight of the total weight of thecomposition. The pharmaceutical composition may also include sweeteningor flavoring agents in an amount of up to about 2.5 or 5% by weightbased on the total weight of the composition. Preferably the antioxidantis α-tocopherol (vitamin E).

[0072] The pharmaceutical composition may also include one or more otherimmunosuppressants such as, for example, a cyclosporin or if a rapamycinis present a FK 506 compound as described above. Cyclosporins comprise aclass of cyclic, poly-N-methylated undecapeptides, generally possessingimmunosuppressive, anti-inflammatory, anti-viral and/or anti-parasiticactivity, each to a greater or lesser degree. The first of thecyclosporins to be identified was the fungal metabolite Cyclosporin A,or Ciclosporine, and its structure is given in The Merck Index, 11thEdition; Merck & Co., Inc.; Rahway, N.J., U.S.A (1989) under listing2759. Later cyclosporins to be identified are cyclosporins B, C, D and Gwhich are also listed in the Merck Index under listing 2759. A largenumber of synthetic analogs are also known and representative examplesare disclosed in EP 296 122, EP 484 281 and GB 2222770. These compoundsare termed collectively “cyclosporins” in this specification.

[0073] The pharmaceutical composition exhibits especially advantageousproperties when administered orally; for example in terms of consistencyand high level of bioavailability obtained in standard bioavailabilitytrials, e.g. 2 to 4 times higher than emulsions. These trials areperformed in animals or healthy volunteers using HPLC or a specific ornonspecific monoclonal kit to determine the level of the macrolide inthe blood. For example, in the test described in Example 3, 10 mg ofrapamycin is administered p.o. to rats and the surprisingly high C_(max)values of between 2670 and 3400 ng/ml are detected by ELISA using aspecific monoclonal antibody. Also, in the test described in Example 4,an emulsion preconcentrate and a microemulsion preconcentratecomposition are found to have much better pharmacokinetic propertiesthan a standard solvent system.

[0074] Pharmacokinetic parameters, for example absorption and bloodlevels, also become surprisingly more predictable and problems inadministration with erratic absorption may be eliminated or reduced.Additionally the pharmaceutical composition is effective with tensidematerials, for example bile salts, present in the gastrointestinaltract. That is, the pharmaceutical composition is fully dispersible inaqueous systems comprising such natural tensides and is thus capable ofproviding microemulsion systems in situ which are stable and do notexhibit precipitation of the active ingredient or other disruption offine particulate structure. The function of the pharmaceuticalcomposition upon oral administration remains substantially independentof and/or unimpaired by the relative presence or absence of bile saltsat any particular time or for any given individual.

[0075] The pharmaceutical composition is preferably compounded in unitdosage form, for example by filling them into orally administrablecapsule shells. The capsule shells may be soft or hard gelatine capsuleshells. Where the pharmaceutical composition is in unit dosage form,each unit dosage will suitably contain between 10 and 100 mg of themacrolide, more preferably between 10 and 50 mg; for example 15, 20, 25,or 50 mg of the macrolide. Such unit dosage forms are suitable foradministration 1 to 5 times daily depending upon the particular purposeof therapy, the phase of therapy and the like.

[0076] However, if desired, the pharmaceutical composition may be indrink solution form and may include water or any other aqueous system,to provide emulsion or microemulsion systems suitable for drinking.

[0077] The utility of the pharmaceutical composition can be observed instandard clinical tests in, for example, known indications of macrolidedosages giving equivalent blood levels of macrolide; for example usingdosages in the range of 2.5 mg to 1000 mg of macrolide per day for a 75kilogram adult and in standard animal models. The increasedbioavailability of the active ingredient provided by the compositionscan be observed in standard animal tests and in clinical trials. If acyclosporin or FK506 compound is included in the pharmaceuticalcomposition, the utility may also be observed in standard clinical testsand animal models. The dosages of macrolide to be used in the clinicaltests are as given above while those for the cyclosporin may be in therange of 25 mg to 1000 mg per day and those for a FK506 compound may be2.5 mg to 1000 mg per day for a 75 kg adult.

[0078] The optimal dosage of macrolide to be administered to aparticular patient must be considered carefully by the treatingphysician as individual response to and metabolism of the rapamycincompound may vary. It may be advisable to monitor the blood serum levelsof the rapamycin compound by radioimmunoassay, monoclonal antibodyassay, or other appropriate conventional means. Dosages of the macrolidewill generally range from 2.5 mg to 1000 mg per day for a 75 kilogramadult, preferably 25 mg to 500 mg, with the optimal dosage beingapproximately 50 to 100 mg per day. Satisfactory results are obtained byadministering about 75 mg per day for example in the form of twocapsules, one containing 50 mg and one containing 25 mg; or threecapsules each containing 25 mg. If a cyclosporin or FK506 compound isincluded in the pharmaceutical composition, the cyclosporin dosage maybe 25 to 1000 mg per day (preferably 50 mg to 500 mg) and the FK 506compound dosage may be 2.5 mg to 1000 mg per day (preferably 10 mg to250 mg).

[0079] The pharmaceutical compositions are particularly useful for thefollowing conditions:

[0080] a) The treatment and prevention of organ or tissue transplantrejection, for example for the treatment of the recipients of heart,lung, combined heart-lung, liver, kidney, pancreatic, skin or cornealtransplants. The pharmaceutical compositions are also indicated for theprevention of graft-versus-host disease, such as sometimes occursfollowing bone marrow transplantation.

[0081] b) The treatment and prevention of autoimmune disease and ofinflammatory conditions, in particular inflammatory conditions with anaetiology including an autoimmune component such as arthritis (forexample rheumatoid arthritis, arthritis chronica progrediente andarthritis deformans) and rheumatic diseases. Specific autoimmunediseases for which the pharmaceutical compositions may be employedinclude, autoimmune hematological disorders (including e.g. hemolyticanemia, aplastic anemia, pure red cell anemia and idiopathicthrombocytopenia), systemic lupus erythematosus, polychondritis,sclerodoma, Wegener granulomatosis, dermatomyositis, chronic activehepatitis, myasthenia gravis, psoriasis, Steven-Johnson syndrome,idiopathic sprue, autoimmune inflammatory bowel disease (including e.g.ulcerative colitis and Crohn's disease) endocrine ophthalmopathy, Gravesdisease, sarcoidosis, multiple sclerosis, primary billiary cirrhosis,juvenile diabetes (diabetes mellitus type I), uveitis (anterior andposterior), keratoconjunctivitis sicca and vernal keratoconjunctivitis,interstitial lung fibrosis, psoriatic arthritis, glomerulonephritis(with and without nephrotic syndrome, e.g. including idiopathicnephrotic syndrome or minimal change nephropathy) and juveniledermatomyositis.

[0082] c) The treatment and prevention of asthma.

[0083] d) The treatment of multi-drug resistance (MDR). The rapamycincompounds suppress P-glycoproteins (Pgp), which are the membranetransport molecules associated with MDR. MDR is particularly problematicin cancer patients and AIDS patients who will not respond toconventional chemotherapy because the medication is pumped out of thecells by Pgp. The pharmaceutical compositions are therefore useful forenhancing the efficacy of other chemotherapeutic agents in the treatmentand control of multidrug resistant conditions such as multidrugresistant cancer or multidrug resistant AIDS.

[0084] The rapamycin compounds also exhibit anti-tumour and antifungalactivity and hence the pharmaceutical compositions can be used asanti-tumour and anti-fungal agents.

[0085] In a further aspect the invention also provides a process for theproduction of a pharmaceutical composition as defined above, whichprocess comprises bringing (1) a hydrophilic phase; (2) a lipophilicphase; and (3) a surfactant into intimate admixture and adding thecompound of the macrolide class. When required, the composition may becompounded into unit dosage form, for example filing the compositioninto gelatine capsules.

[0086] Optionally further components or additives, in particular ahydrophilic phase co-component, for example ethanol, may be mixed withcomponents (1), (2) and (3) or with or after addition of macrolide.

[0087] The composition may be combined with sufficient water orsufficient of an aqueous solvent medium such that a microemulsion oremulsion is obtained.

[0088] The contents of all the references referred to above especiallythe exemplified compounds are hereby incorporated by reference, and eachof the exemplified compounds may be used as a macrolide in the exampleslisted below.

[0089] The following examples illustrate compositions in unit dosageform, suitable for use, for example in the prevention of transplantrejection or for the treatment of autoimmune disease, on administrationof from 1 to 5 unit dosages/day. The examples are described withparticular reference to rapamycin but equivalent compositions may beobtained employing any other macrolide.

EXAMPLE 1 Refined glycerol-Transesterified Corn Oil is Prepared asFollows

[0090] Substantially-glycerol free glycerol-transesterified corn oil isslowly cooled to a temperature of +20° C. and kept at this temperaturefor one night. The corn oil is centrifuged at an acceleration of 12 000G and at a flow rate of 103 kg/h in a continuous flow centrifuge to givea liquid phase (62 kg/h) and a sediment-containing phase (41 kg/h). Theliquid phase is slowly cooled to +8° C. and kept at this temperature forone night. The liquid phase is then centrifuged at an acceleration of 12000 G and at a flow rate of 112 kg/h to give a liquid phase (76.2 kg/h)and a sediment-containing phase (35.8 kg/h). The liquid phase is“refined glycerol-transesterified corn oil”. Alternatively an improvedproduct may be obtained by effecting the centrifugation in three steps,e.g. at +20° C., +10° C. and +5° C.

[0091] The process is characterised by a slight percentage reduction inthe mono-glyceride component in the refined glycerol transesterifiedcorn oil as compared to the starting material (e.g. 35.6% compared to38.3%).

EXAMPLE 2

[0092] The refined glycerol-transesterified corn oil obtained asdescribed in Example 1 is used in the preparation of the following oralunit dosage form QUANTITY COMPONENT (mg/capsule) Rapamycin  20.0 1)Ethanol  75.0 2) 1,2-propylene glycol  81.0 3) refined oil 121.5 3)Cremophor RH40 202.5 Total 500.0

[0093] The rapamycin is suspended in (1) with stirring at roomtemperature and (2), (3) and (4) are added to the obtained solutionwhile stirring. The obtained mixture is filled into size 0 hard gelatinecapsules and sealed using the Quali-Seal technique.

EXAMPLE 3 Pharmokinetics

[0094] Two formulations prepared as set out in Example 2 are used:Formulation Component Amount % A Tween 80 41.5% Maisine 24.9% Propyleneglycol 16.6% Ethanol 15.0% Rapamycin  2.0% B Cremophor RH40 41.5%Maisine 24.9% Propylene glycol 16.6% Ethanol 15.0% Rapamycin  2.0%

[0095] Formulation A is an emulsion preconcentrate and formulation B isa microemulsion preconcentrate. 6 male Wistar rats of mean body weightof 300 g are used per form. One day before treatment, food is withdrawnfrom the rats but the rats are permitted free access to water. The ratsare then anesthetized by intraperitoneal injection of 2×1 ml 20%urethane and a permanent catheter is inserted into the right venajugularis to permit blood sampling. 500 ml/animal of the formulation isadministered by gastric intubation 20 hours after the surgery. A totaldose of 10 mg of drug per animal is administered. Blood samples of 0.7ml are taken from the jugular catheter of each animal 15 minutes beforedrug administration and then 0.17, 0.5, 1, 1.5, 2, 3, 5 and 8 hoursafter drug administration. The samples are kept in heparinized tubes andare analysed by means of ELISA using microtitre plates coated withrapamycin specific antibodies. The animals are killed immediately aftertaking the last blood sample. The results are given in the followingtable: AUC (0-8 CV C_(max) CV t_(max) CV Form hrs) [ng.h/ml] [%] [ng/ml][%] [hrs] [%] A 11951 44 2671 42 3.8 29^(•)  B 13826 13 3405 30 4.0 35⁺

[0096] The results indicate that rapamycin is well absorbed.

Example 4 Comparison

[0097] Formulations A and B are compared to a formulation comprising38.6% corn oil, 41.6% Labrafil M21/25C, 17.8% ethanol and 2% rapamycin(formulation C). The same procedure as used in example 3 is used exceptthat the animals each receive a total dose of 0.5 mg of drug.

[0098] The results are given in the following table: AUG (0-8 CV C_(max)CV t_(max) CV Form hrs) [ng.h/ml] [%] [ng/mI] [%] [hrs] [%] A 105.8 2831.22 35 1.6   51^(•) B 96.6 32 36.13 60 0.4 30 C 36.2 31 7.83 27 3.0 78

[0099] The results indicate that formulations A and B provide muchbetter pharmacokinetic properties than formulation C.

EXAMPLE 5

[0100] An active compound of the FK 506 class or rapamycin class e.g.compound A is made up into a microemulsion preconcentrate having thefollowing composition by weight 2% active compound 44% Cremophor RH4026.4% corn-oil mono-, di-, tri-glycerides, 17.6% 1,2 propylene glycoland 10% ethanol.

1. A pharmaceutical composition comprising a macrolide and a carrier medium comprising a hydrophilic phase, a lipophilic phase and a surfactant.
 2. A composition according to claim 1 in the form of an emulsion or a microemulsion preconcentrate.
 3. A composition according to claim 1 or claim 2 in which the lipophilic phase comprises 10 to 85% by weight of the carrier medium.
 4. A composition according to any one of claims 1 to 3 in which the surfactant comprises 5 to 80% by weight of the carrier medium.
 5. A composition according to any one of claims 1 to 4 in which the hydrophilic phase comprises 10 to 50% by weight of the carrier medium.
 6. A composition according to any one of claims 1 to 5 in which the compound of the rapamycin class is present in an amount of 2 to 15% by weight of the composition.
 7. A composition according to any one of claims 1 to 6 in which the macrolide is a compound of the rapamycin class.
 8. A composition according to any one of claims 1 to 6 in which the macrolide is a FK 506 compound.
 9. An microemulsion preconcentrate carrier medium for an orally administrable active agent other than a cyclosporin which comprises i) a reaction product of a castor oil and ethylene oxide, ii) a transesterification product of a vegetable oil and glycerol comprising predominantly linoleic acid or oleic acid, mono-, di- and triglycerides or a polyoxyalkylated vegetable oil, iii) 1,2 propylene glycol and iv) ethanol. 